U.S. President Donald Trump’s assertion that taking paracetamol during pregnancy is linked to autism in kids has been debunked by a large evidence review.

Researchers say the new study published Saturday should put women at ease should they need to use these painkillers.

Last year, Trump warned pregnant women against using Tylenol — a U.S. brand name for paracetamol — during pregnancy, arguing that its use “can be associated with a very increased risk of autism.”

The position was driven by Republicans pushing the MAHA — Make America Healthy Again — movement led by U.S. Health Secretary Robert F. Kennedy Jr. But it has split politicians and health experts on both sides of the Atlantic and confused citizens.

While the U.S. Food and Drug Administration ordered a new safety warning be added to Tylenol leaflets, the European Medicines Agency said at the time there was no evidence of a link between paracetamol use in pregnancy and autism. Medical professionals raised concerns that pregnant women would have no treatment for fever or pain, and may be vilified for the rise in autism in recent decades.

Now, a large review of 43 studies, published in The Lancet Obstetrics, Gynaecology & Women’s Health, found there is no evidence of a link — contradicting the U.S. studies used to recommend against its use in the U.S.

“We found no clinically important increase in the risk of autism, [attention deficit hyperactivity disorder (ADHD)] or intellectual disability of the children where the mothers took paracetamol during pregnancy,” said Asma Khalil, a consultant obstetrician and fetal medicine specialist at St George’s Hospital in London, who led the study.

“The important message to the millions of pregnant individuals is the fact that actually paracetamol is safe to use in pregnancy,” she added. “It remains to be the first line of treatment that we would recommend if the pregnant woman has pain or fever in pregnancy.”

While previous studies did suggest small associations between paracetamol in pregnancy and increased risks of autism and ADHD, the Lancet researchers said these were often based on studies prone to biases.

In particular, the U.S. administration cited a study published last summer which found a link between paracetamol during pregnancy and increased incidence of neuro-developmental disorders (NDDs). But in this review “there are several studies [which] suffer or are vulnerable to bias,” Khalil said. “The potential implications of not accounting for these confounders is that you draw their own conclusions.”

The Lancet’s evidence review instead focused on studies with the most rigorous research methods, such as those at low risk of bias, those with sibling comparisons and with at least five years of follow up — and found no link.

In particular, sibling-comparison studies allow researchers to compare children born to the same mother, who only took paracetamol during one of the pregnancies. They take into account shared genetic factors, shared family and long-term parental characteristics.

“Our findings suggest that previously reported links are likely to be explained by genetic predisposition or other maternal factors such as fever or underlying pain, rather than a direct effect of the paracetamol itself,” Khalil said.

Public health experts, the EMA and the European Commission, pushed back against Trump’s position last year, arguing there was no evidence to support it.

“While the impact of last year’s announcement has been extensive, I hope the findings of this study bring the matter to a close,” Grainne McAlonan, professor of translational neuroscience at King’s College London, said. 

“Expectant mothers do not need the stress of questioning whether medicine most commonly used for a headache could have far reaching effects on their child’s health,” McAlonan said.